Wolf RF Systems
 

Specifications AS-AYL-4  Loop System

  • Antenna type:                          Terminated loop
  • Pattern:                                   Cardioid, switched in four directions
  • Peak front-to-back:                 Greater than 20 dB, typically 30 dB

  • Feedpoint impedance:             50 ohms nominal; low-loss transformer matching to the antenna

  • Frequency range:                    Very low frequencies to  8 MHz, using published dimensions. With preamp on, bandpass is limited to 1.8-5 MHz

  • Direction change:                   Feedpoint/termination switching relays
  • Direction control:                    Connected with a 6-conductor control cable

  • RF connection (antenna):       SO-239 (UHF) connectors at control box and outdoor relay box

  • RF connection (radio):            Phono connector output to receiver external antenna input

  • Termination Adjustment:         Eight resistances from 340 to 680 ohms, selected by front-panel rotary switch

  • Power requirements:               +12 to 15 VDC, 400 mA max., (provided by customer, to be fused at 0.5 A)

  • Preamplifier:                           15 dB gain, feedback type, using a silicon NPN transistor
  • Filter passband:                      ±2 dB from 1.80 to 4.5 MHz
  • Filter stopband:                       –55 dB at 7 MHz, –50 dB below 1450 kHz (typical)
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    Required Area

    The AYL-4 K9AY Loop System requires approximately 15 feet in four directions from the center of the antenna, plus additional distance depending on the guying method.  The base of the supporting pole and the ground rod are located at the center. With the AYL-M kit, 21 feet in each of the four directions is required. The center support is 25 feet high, and must clear any objects above.

     

    Plot of the K9AY loop Antenna Response.  

     
    Measured Plot of the AS-AYL-4 Control Box -
    Amplifier and Filter Response

    Preamp Switched On

     

    Measured Plot of the AS-AYL-4 Relay Box

    Matching Balun Transformer

    Top Plot is the S11 Response with the Antenna terminated into 450 Ohms

    Bottom Plot Shows a Return Loss of 25 dB into the Balun with 450 Ohms Termination